How to move one, but not both, set of labels in facet

Consider the two following examples:

ggplot(mtcars, aes(x = wt, y = qsec))  
  geom_point()  
  facet_grid(cols = vars(vs), rows = vars(gear), scales = "free")  
  geom_vline(aes(xintercept = mean(wt)))

Notice how this produces the same values of xintercept for geom_vline in the same column, even with scales = "free" as was explained in

We now get the xintercepts displayed separately in each facets. However, now the labels of both faceting variables are above the graphs. How do I move them so that, like in the facet_grid, one variable's labels are on top and one on the right? I tried using strip.position = c("top", "right") in facet_wrap, but that gives the following error:

Error in match.arg(strip.position, c("top", "bottom", "left", "right")) : 
  'arg' must be of length 1

So then how to do it?

CodePudding user response：

Adapted from